Astronomy and the heliocentric model
Nicolaus Copernicus
1473–1543 · Poland
Copernicus was born in Toruń in 1473 and raised by an uncle who became a bishop, an advantage that secured him a canonry at Frombork and the freedom to study. He read law and medicine in Italy, learned Greek, and returned north to a life divided between church administration, medicine, and astronomy.
Working from his own observations and from the records of ancient astronomers, he came to distrust the tangled system of epicycles that kept the Earth at the center. In De revolutionibus orbium coelestium, published in the year of his death, he set out a model in which the Earth turns daily on its axis and travels yearly around the Sun.
He was cautious, and the book appeared with a preface — added by a Lutheran theologian — describing the model as a convenience for calculation rather than a claim about the world. Kepler and Galileo read it as the latter, and the center of the universe began to move.
Unknown author · Public domain
Known for
Heliocentrism
The claim that the Sun, not the Earth, sits at the center of the planetary system — and the slow, contested work of making it fit observation.
For centuries the Earth had been assumed to sit still at the center of the cosmos, with the Sun, Moon, and planets circling it on nested spheres. Copernicus found that arrangement increasingly awkward, because the planets' motions had to be patched with epicycles to match what astronomers actually saw.
His alternative put the Sun near the center and set the Earth spinning on its axis and orbiting once a year. It explained the apparent backward loops of the planets as a consequence of the Earth's own motion, and it made the ordering of the planets follow naturally from their periods. The idea was not proved until Galileo's telescope and Kepler's ellipses, but it changed the questions astronomy asked.
Hosted
A solitary supper at Frombork · 1540 · Frombork, Royal Prussia
Attended
A Borgia table in Rome · 1498 · Rome, Italy
A study in exile · 1513 · Florence, Italy
A commonwealth imagined · 1516 · London, England
The printer's house · 1520 · Basel, Switzerland
The Diet at Augsburg · 1530 · Augsburg, Germany
An evening at Fontainebleau · 1535 · Fontainebleau, France